2573. Find the String with LCP

We define the lcp matrix of any 0-indexed string word of n lowercase English letters as an n x n grid such that: - lcp[i][j] is equal to the length of the longest common prefix between the substrings word[i,n-1] and word[j,n-1]. Given an n x n matrix lcp, return the alphabetically smallest string word that corresponds to lcp. If there is no such string, return an empty string. A string a is lex